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To determine if lubricating oil is diluted with fuel oil or engine coolant is causing low oil pressure, perform the following: ‪

  1. Acquire a lubricating oil sample from the engine oil pan.
  2. Visually examine lubricating oil sample for presence of engine coolant or fuel oil.
    1. If coolant or fuel oil are not present, check for a faulty oil pressure gage sensor, refer to Section .
    2. If water or fuel oil are present, refer to Section .

Note: Blockage of the engine water pump weep hole can allow coolant that has leaked past a faulty water pump oil seal to enter the lubricating oil. Inspect the weep hole for blockage.

Contaminated Lubricating Oil Resolution

Perform the following steps to resolve contaminated lubricating oil: ‪

  1. Drain engine oil pan, refer to Section .
  2. Refill engine crankcase with new oil; refer to Section .
  3. Verify lubricating oil replacement; refer to Section .
Test Replaced Lubricating Oil

Perform the following to determine if replaced lubricating oil resolved low oil pressure: ‪

  1. Install the Diagnostic Data Reader to the vehicles Display Data Line Adaptor, see Figure 24089 ; refer to OEM guidelines.
  2. Start and run the engine speed at 1800 r/min.
  3. Visually examine the DDR for oil pressure reading.
    1. If the DDR indicates oil pressure greater than 241 kPa (35 lb/in.2 ), at 1800 r/min, shut down the engine and disconnect the DDR. No further troubleshooting is required.
    2. If the DDR indicates oil pressure less than 241 kPa (35 lb/in.2 ), at 1800 r/min, shut down the engine and disconnect the DDR. Check for faulty oil pressure gage sensor; refer to Section .